As digital camera, digital vidicon and camera phone continually advance towards higher imaging quality and higher definition, non-spherical lens has been applied increasingly. For this, the glass with medium refractive index, low dispersion and high transmittance has become increasingly popular in the market. In the meantime, in order to reduce processing difficulty and production cost, high-precision molding technology becomes the first choice for applying optical glass to manufacture optical lens. However, the optical glass applicable to high precision molding must be obtained with lower transition temperature, which raises higher requirements for optical glass researchers.
An optical glass disclosed by China Patent (Application No.: 201010554499.2) is unfavorable to high-precision molding because its glass-transition temperature (GTT) is about 600° C.
An optical glass recorded in JP 2004-217513 is low in glass transmittance due to higher Nb2O5, Bi2O3 and WO3 contents
A Chinese patent (Application No.: 201010299001.2) discloses an optical glass containing a variety of B2O3, which improves the volatility when the glass is molten, and produces insufficient chemical stability and devitrification resistance of glass.